A typical display system comprises a display device such as a cathode ray tube (CRT) display and a host computer system connected to the display device. In operation, the computer system generates image data for producing a picture on the screen of the display device. Conventionally, the computer system initially generates the image data in the digital domain. A digital to analog convertor in the computer system then converts the image data into analog video signals for transfer to the display device. Such display systems provide acceptable performance provided the display device is responsive to analog video signals. However, some display devices, for example liquid crystal display screens, require a digital video signal.
Furthermore, some display devices include digital signal processing systems for processing input video signals in the interest of performance enhancement. The operation of such display devices, hereinafter referred to as digital display devices, is dependent on the conversion of the analog video signal generated by the computer system back into the digital domain. However, such conversion introduces noise and instability to the display system. In conventional systems, each pixel of an image is represented by a fixed number of bits. Therefore each pixel has a correspondingly finite colour depth. Current liquid crystal displays allocate between 4 and 6 bits per colour. However, in more recent digital display technologies, the colour depth is 8 bits per colour. Some digital video output devices or "Palettes" can now provide 10 bits per colour. Furthermore, the number of bits per colour can vary in such Palettes from one colour to the next. Typically, green is allocated more bits than red and blue, for example. As the cost of integrated electronic display devices such as liquid crystal display panels reduces, a corresponding market trend is emerging towards digital display devices in preference to conventional analog display technologies. It will be appreciated that such digital displays may be categorised in the market-place by screen-size, refresh rate, resolution, and colour depth.